Light-sensitive materials

ABSTRACT

PHOTOGRAPHIC MATERIALS COMPRISING A SUPPORT AND AT LEAST ONE LAYER OF LIGHT-SENSITIVE SILVER HALIDE EMULSION CONTAINING A WATER-SOLUBLE MERCURY(II) COMPOUND HAVING ONE OF THE FOLLOWING FOMRULAE:   (M-O3S-X1-S)2-HG AND M-O3S-X2-S-HG-Y   WHEREIN: X1 IS A BIVALENT ORGANIC RADICAL, X2 STANDS FOR AN ALIPHATIC OR AROMATIC BIVALENT GROUP, M REPRESENTS HYDROGEN, ALKALI METAL, ALKALINE EARTH METAL, AMMONIUM, GUANIDINE OR AN ORGANIC AMIND, AND Y STANDS FOR AN ALIPHATIC, ALICYCLIC, AROMATIC OR HETEROCYCLIC RADICAL, SAID RADICALS INCLUDING THE SUBSTITUTED DERIVATIVES THEREOF ARE DESCRIBED. THE PHOTOGRAPHIC MATERIAL HAS IMPROVED STABILITY AND FOGGING CHARACTERISTICS.

United States Patent Ofice 3,567,454 Patented Mar. 2, 1971 3,567,454LIGHT-SENSITIVE MATERIALS Jozef Frans Willems, Wilrijk, Robrecht JuliusThiers, Brasschaat, and Adam Marcel Schouwenaars, Edegem, Belgium,assiguors to Gevaert-Agfa N.V., Mortsel, Belgium No Drawing. Filed Nov.21, 1967, Ser. No. 684,622

Claims priority, application Great Britain, Dec. 12, 1966,

55,445/ 66 Int. Cl. G03c 1/34 US. Cl. 96-109 7 Claims ABSTRACT OF THEDISCLOSURE Photographic materials comprising a support and at least onelayer of light-sensitive silver halide emulsion containing awater-soluble mercury(II) compound having one of the following formulae:

wherein:

X is a bivalent organic radical,

X stands for an aliphatic or aromatic bivalent group,

M represents hydrogen, alkali metal, alkaline earth metal,

ammonium, guanidine or an organic amine, and

Y stands for an aliphatic, alicyclic, aromatic or heterocyclic radical,said radicals including the substituted derivatives thereof aredescribed. The photographic material has improved stability and foggingcharacteristics.

This invention relates to improved light-sensitive silver halideemulsions.

Light-sensitive silver halide emulsions are in general characterised bytheir sensitivity, gradation and fog.

As is well-known, sensitivity, gradation and fog are determined by theway in which the silver halide emulsion is prepared and by the use ofspecial chemical ingredients elfecting a desired improvement or reuslt.Addenda to the emulsion, which are of particular importance for thestability of the light-sensitive characteristics of a silver halideemulsion are the so-called stabilizers.

Stabilizers or antifoggants protect the light-sensitive silver halideemulsions against spontaneous formation and growth of fog known aschemical fog during prolonged storage or storage at high temperaturesand humidities or during development to maximum contrast and speed.Indeed, the fog increases with the degree and temperature ofdevelopment, and, in constant development circumstances, with the timethe light-sensitive emulsion is stored and with the temperature and therelative humidity of the atmosphere wherein the emulsion is stored. Itis evident that a light-sensitive emulsion should be obtained which isas stable as possible at high temperature and high relative humidity forinstance in view of its use in tropical countries.

It is known to protect light-sensitive silver halide emulsions againstthe growth of chemical fog during storage by addition of stabilizers ofthe triazolopyrimidine type (azaindolizines). Heterocyclic thioxo andmercapto compounds too have been proposed for this purpose but show thedisadvantage of impairing the sensitivity and gradation. The samedisadvantageous influence on the sensitivity occurs with the knownmercury compounds such as simple anorganic mercury salts, additioncomplexes of mercury with amines, organic mercury salts and heterocyclicmercury compounds. Indeed, these compounds, when used in theconcentration necessary for obtaining a sufficient antifogging action,have a considerable desensitizing effect.

It is also known that emulsions stabilised with compounds of thetriazolopyrimidine type still show a tendency to fog formation inextreme storage circumstances i.e. at very high temperatures andhumidities and in extreme development circumstances e.g. rapidprocessing at elevated temperatures. The addition to these emulsions ofthe above known mercury compounds reduces the fogging tendency but, asmentioned above, at the cost of a reduction of the sensitivity.

It has now been found that mercury(II) compounds corresponding to one ofthe following general Formulae I and II X, represents a bivalent organicradical e.g. an aliphatic, aromatic or heterocyclic bivalent radicalsuch as alkylene including substituted alkylene, arylene includingsubstituted aralkylene and a bivalent radical comprising a heterocyclicnucleus including a substituted heterocyclic nucleus,

X stands for an aliphatic or aromatic bivalent group such as alkyleneincluding substituted alkylene, arylene including substituted arylene,and aralkylene including substituted aralkylene,

M represents hydrogen, an alkali metal or alkaline earth metal,ammonium, guanidine, an organic amine, etc., and

Y stands for an organic aliphatic, alicyclic, aromatic or heterocyclicradical said radicals including the substituted alkyl, aryl includingsubstituted aryl and a heterocyclic nucleus including a substitutedheterocyclic nucleus,

are particularly good stabilizers and antifoggants for photographiclight-sensitive silver halide emulsions without causing an appreciabledesenitization of the light sensitive silver halide emulsion material.

Moreover, it has been found that these mercury(II) compounds are verysuitable for use in combination with stabilizers of thetriazolopyrimidine type, particularly in extreme storage and developmentcircumstances in order to reduce the fogging tendency of thelight-sensitive emulsion without giving rise to an appreciabledesensitization thereof.

The high-water-solubility, obtained by the presence of the sulphonicacid group in the mercury(II) compounds of the above general formulaguarantees a homogeneous distribution of the stabilizer in the emulsion.

The following is a non-limitative list of particularly suitablemercury(II) compounds for use as stabilizers for photographiclight-sensitive silver halide emulsions according to the presentinvention:

The watersoluble mercury(II) mercaptides of use according to the presentinvention can be prepared by allowing to react a mercury (II) salt suchas mercury(II) acetate or mercury(II) chloride with the correspondingmercapto compound. The said mercury(II) mercaptides can also be obtainedin a very pure form by reaction of mercury(II) oxide with thecorresponding mercapto compound.

The mercury(II) compounds corresponding to the above general Formula IIcan be prepared by allowing to react the corresponding organo-mercurysalts such as the chlorides, bromides or acetates or the correspondingorganomercury hydroxides with the sulphonated mercaptans.

The following preparations illustrate more particularly how themercury(II) compounds are prepared.

PREPARATION l.COMPOUND 1 (a) To a solution of 10.75 g. (0.05 mole) ofthe guanidine salt of 3-mercapto-propane sulphonic acid in 55 ccs. ofwater a solution of 7.95 g. (0.025 mole) of mercury(II) acetate in 35ccs. of water was added. The water was distilled off under reducedpressure and the mercury(II) mercaptide formed was recrystallized frommethanol.

.(b) To a solution of 43 g. (0.2 mole) of the guanidine salt of3-mercapto-propane sulphonic acid in 500 ccs. of water, 21.6 g. (0.1mole) of yellow mercury(II) oxide 4 were added with vigorous stirring.After evaporation of the water the residue was washed with acetone.

PREPARATION 2COMPOUND 3 To a solution of 13.15 g. (0.05 mole) of theguanidine salt of o-sulpho-benzyl mercaptan in 300 ccs. of water asolution of 7.95 g. (0.025 mole) of mercury(II) acetate in 50 ccs. ofwater was added. A white precipitate formed, which was filtered bysuction and washed with alcohol.

PREPARATION 3.COMPOUND 4 To a solution of 12.8 g. (0.05 mole) of theguanidine salt of Z-mercapto-4-methyl-4-sulpho-pentane in 400 ccs. ofwater a solution of 7.95 g. (0.025 mole) of mercury(II) acetate in 50ccs. of water was added. After evaporation of the water the residue wasdigested with methanol and dried.

PREPARATION 4.-COMPOUND 5 To a solution of 7.7 g. (0.03 mole) ofS-(m-sulphophenyl)-triazoline-3-thione in ccs. of water a solu tion of4.78 g. (0.015 mole) of mercury(II) acetate in 25 ccs. of water wasadded. The precipitate formed was filtered by suction and washed withwater and ethanol. The mercury(II) mercaptide formed is soluble indiluted sodium hydroxide.

PREPARATION 5.COMPOUND 7 (a) 79 g. of mercury(II) acetate, 15.5 g. ofallyl alcohol and 150 ccs. of methanol were refluxed for 5 min. Theexcess of methanol and the acetic acid formed were distilled oiT underreduced pressure. The product obtained (32 g.) had an oxygen content of18.76% (calculated: 18.4%).

(b) 3.48 g. of the product obtained in ,(a) were treated with an aqueoussolution of 2.15 g. of the guanidine salt of 3-mercapto-propanesulphonic acid. The water was distilled 01f under reduced pressure andthe residue purified with ethanol.

PREPARATION 6.COMPOUND 8 A solution of 10 g. of allylurea in ccs. ofmethanol, 31.9 g. of mercury(II) acetate and 6 ccs. of acetic acid wererefluxed for 6 hours. The excess of methanol and the acetic acid formedwere distilled off under reduced pressure.

To the residue an aqueous solution of 21.5 g. of the guanidine salt of3-mercapto-propane sulphonic acid was added with vigorous stirring. Themercury(II) compound formed was purified with ethanol.

PREPARATION 7.-COMPOUND 12 (a) To a solution of 13.5 g. of mercury(II)chloride in 200 ccs. of water a solution of 6 g. of sodium hydroxide in25 ccs. of water was added. The precipitate formed was filtered 01f bysuction and washed with water until no chloride ions could be indicatedanymore.

The product was suspended in 50 ccs. of water and then an aqueoussolution of 22 g. of salicylic acid was added with stirring. After somehours the suspension formed was concentrated by evaporation and the residue digested with ethanol.

(b) 4.3 g. of the compound obtained according to (a) were treated withan aqueous solution of 1.8 g. of the sodium salt of 3-mercapto-propanesulphonic acid. After having concentrated the solution by evaporationthe residue was purified with ethanol.

As compared with the known mercury compounds used as stabilizers themercury(II) compounds according to the present invention when used inthe appropriate concentration do not cause or only to a slight extent adecrease in sensitivity.

The antifoggants according to the present invention are particularlysuitable for use in combination with cornpounds which sensitize theemulsion by development ac celeration for example compounds of thepolyoxyalkylene type such as alkylene oxide condensation products asdescribed among others in United States Pat. 2,531,832 and 2,533,990, inUnited Kingdom Pat. 920,637, 940,051, 945,340 and 991,608 and in BelgianPat. 648,710 and onium derivatives of amino-N-oxides as described in USpatent application Ser. No. 573,801, filed Aug. 22, 1966, and nowpending.

The stabilizers according to the inventions can also be used incombination with other known stabilizers for instance with heterocyclicnitrogen containing thioxo compounds such as benzothiazoline-Z-thioneand 1-phenyl-2- tetrazoline-S-thione and, as said above, preferably withcompounds of the hydroxytriazolopyrimidine type (azaindolizines).

The stabilizers according to the present invention may be incorporatedinto any type of light-sensitive material comprising a silver halideemulsion layer e.g. a spectrally sensitized or non-sensitized emulsionlayer, X-ray emulsion layer, and an emulsion layer sensitive toinfra-red radiation. They may be incorporated into high-speed negativematerials as well as into rather low speed positive materials. Varioussilver salts may be used as lightsensitive salt e.g. silver bromide,silver iodide, silver chloride, or mixed silver halides e.g. silverchloro-bromoide or silver bromo-iodide.

The silver halides are dispersed in the common hydrophilic colloids suchas gelatin, casein, zein, polyvinyl alcohol, carboxymethylcellulose,alginic acid, etc., gelatin being however favoured.

The stabilizing agents are generally incorporated into the silver halideemulsion layer of the light-sensitive material; they may be added to theemulsion during no mat ter what step of emulsion preparation; however,they are preferably added to the photographic emulsion after thechemical ripening and just before coating of the emulsion. The addendaaccording to the present invention are incorporated into thephotographic emulsions accord ing to the methods well known in emulsionpreparation. For instance they can be added to the emulsion in the formof a solution or of a dispersion according to the methods applied forincorporating colour couplers in the emulsion. Instead of incorporatingthe compounds of the invention into the emulsion layer they can also beincorporated into a water-permeable layer e.g. a gelatin covering layeror intermediate layer.

The amount of mercury(II) compound employed in the light-sensitivesilver halide material depends on the particular type of emulsion andthe desired effect and can vary within very wide limits. The optimumamount of mercury(II) compound to be added can be determined for eachparticular emulsion in a very simple way by application of the usualtests. Usually said compounds are employed in a ratio of about 0.1 mg.to about 30 mg. per mole of silver halide.

The light-sensitive emulsions may be chemically as well as opticallysensitized. They may be chemically sensitized by eifecting the ripeningin the presence of small amounts of sulphur containing compounds such asallylthiocyanate, allyl thiourea, sodium thiosulphate, etc. Theemulsions may also be sensitized by means of reductors for instance tincompounds as described in our French patent specification 1,146,955 andin our Belgian patent specification 568,687, imino-aminomethanesulphinic acid compounds as described in our British patentspecification 789,823 and small amounts of noble metal compounds such asof gold, platinum, palladium, iridium, ruthenium and rhodium.

Other addenda such as hardening agents, wetting agents, plasticizers,colour couplers, developing agents and optical sensitizers can beincorporated into the emulsion in the usual way.

The following examples illustrate the present invention.

Example 1 A high sensitive gelatino silver bromoiodide emulsion (:4.5mole percent of iodide) is divided into six aliquot portions A, B, C, D,E and F.

To emulsion portion B is added per mole of silver halide 1.2 l0millimole (3 mg.) of mercury (II) cyanide, to emulsion portion C 0.6 10-millimole (3.8 mg.) of compound 1, to emulsion portion D 1.2 10-millimole (7.5 mg.) of compound 1, to emulsion portion E 2.0 10-millimole (10 mg.) of compound 7 and to emulsion portion F l.2 10-millimole (6.6 mg.) of compound 8. The six emulsions are then coated ona subbed cellulose triacetate support and dried whereupon the sixmaterials thus obtained are stored for 5 days in an atmosphere of 57 C.and 34% of relatively humidity.

The stored materials as well as six identical freshly prepared materialsare exposed and developed for 5 minutes at 20 C. in a developing bathwith the following composition:

Water-800 ccs.

p-Monomethylaminophenol sulphate-15 g.

Sodium sulphite (anhydrous)50 g.

Hydroquinone--6 g.

Sodium carbonate (anhydrous)-32 g.

Potassium bromide-2 g.

Water up to1000 ccs.

After the treatment in a stop bath, rinsing and fixing of the materialsthe following sensitometric results are obtained.

TABLE Freshly prepared materials Stored materials Relative RelativeGradaspeed Gradaspeed Material Fog tion (percent) Fog tion (percent) Agelatino silverbromoiodide emulsion (0.35 mole percent of iodide)comprising per mole of silver halide 400 mg. of 5 methyl 7hydroxy-s-triazolo [LS-a]- pyrimidine and '5 mg. of1-phenyl-2-tetrazoline 5-thione as stabilizers, 200 mg. of developmentaccelerator corresponding to the formula:

wherein x has a value of about and 2 g. of saponin as coating aid, isdivided into 4 aliquot portions.

To three of these emulsion portions is added an amount of compound 1 aslisted in the table below.

The four emulsions are coated on both sides of a cellulose triacetatesupport, which has been provided on both sides with a subbing layer, insuch a way that per sq. m. an amount of silver halide equivalent to 36g. of silver nitrate (both sides taken together) is present.

The emulsion layers are then overcoated with a gelatin antistress layer.

The four materials A, B, C and D obtained are then stored for 36 hoursin an atmosphere of 57 C. and 34% of relative humidity.

Thereupon the said four materials as well as four identical freshlyprepared materials are exposed to X-rays with an X-ray radiation sourceof 80 kv. and developed for 8 min. at 20 C. in a common X-ray developerhaving the following composition:

Water-800 ccs.

p-Monomethylaminophenol hemisulphate-4 g. Hydroquinne-10 g.

Anhydrous sodium sulphite65 g.

Anhydrous sodium carbonate-45 g. Potassium bromide g.

Water up to-1000 ccs.

The results obtained are listed in the following table.

TABLE Amount of Freshly prepared stabilizer materials Fog per moleproduced of silver Relative in stored Material halide, mg. Fogsensitivity materials None 0. O8 100 0. 36 3 0. 08 112 0. 2a 6 0.08 1120. O. 05 100 0. 04

Example 3 A gelatino silverbromoiodide emulsion as described in Example2 is divided into 4 aliquot portions.

To three of these emulsion portions is added an amount of mercury(II)compound as listed in the table below.

The four emulsions are then coated as described in Example 2 on acellulose triacetate support and the resulting materials A, B, C and Dare further treated as described in Example 2 with the difference,however, that the development now takes place at 26 C.

The results obtained are listed in the following table.

TABLE Fog produced on development Amount of mercury (11) for 8 min. at26 0.

mercaptide per mole of silver halide Material Example 4 TABLE Freshlyprepared A mount of materials mercury(II) Fog mercaptide per Relativeproduced mole of silver Gradaspeed in stored Material halide Fog tion(percent) materials A None 0. 11 2. 32 100 0.32 B 2.5 mg. of 0. 11 2.1099 0.16

, compound 1. C 2.9 mg. of 0. l1 2. 25 99 0. 14

compound 3. D 2.8 mg. 0.12 2. 21 100 0.1.4

compound 4. E 2.3 mg. of 0. 12 2. 23 102 O. 14

compound 7. F 2.3 mg. of 0.11 2. 99 0. 14

compound 8. G 2.3 mg. of 0.11 2. 21 99 0. 14

compound 10. H 2.3 mg. of 0.12 2. 24 102 0.14

compound 12.

We claim: e e

1. Photographic material comprising a support and at ll lliiiiiilll lllllllll l l llllllllll lillllllllll i llllillll till least onelight-sensitive silver halide emulsion layer comprising in said emulsionlayer or in at least one waterpermeable layer coated at the same side ofthe support as the said emulsion layer at least one water-solublemercury(II) compound corresponding to one of the general Formulae I andII:

[MOSS-XIS]Q H and MOtSX2SHgY I II 10 wherein:

X is a bivalent organic radical, X stands for an aliphatic or aromaticbivalent group, M represents hydrogen, alkali metal, alkaline earthmetal, 15 ammonium, guanidine or an organic amine, and

Y stands for an aliphatic, alicyclic, aromatic or heterocyclic radical,said radicals including the substituted derivatives thereof,

said mercury(II) compound being present in an amount 20 sufficient toimprove the stability or fogging characteristics of said materialwithout appreciable desensitization thereof.

2. Photographic material according to claim 1, wherein said mercury(II)compound corresponds to the for- 25 mula:

wherein X stands for alkylene including substituted alkylene, aryleneincluding substituted arylene, aralkylene including substitutedaralkylene or a bivalent group conprisin a heterocyclic nucleusincluding a substituted heterocyclic nucleus, and M represents hydrogen,alkali metal, alkaline earth metal, ammonium, guanidine or an organicamine.

3. Photographic material according to claim 1, wherein said mercury(II)compound corresponds to the formula:

X stands for alkylene including substituted alkylene,

arylene including substituted arylene, or aralkylene includingsubstituted aralkylene,

Y stands for alkyl including substitute dalkyl, aryl includingsubstituted aryl or a heterocyclic nucleus including a substitutedheterocyclic nucleus, and

M stands for hydrogen, alkali metal, alkaline earth metal,

ammonium, guanidine or an organic amine.

4. Photographic material according to claim 1, wherein said mercury(II)compound is present in an amount of from 0.1 mg. to 30 mg. per mole ofsilver halide.

5. Photographic light-sensitive silver halide material according toclaim 1, wherein said material also includes a stabilizer of thehydroxytriazolopyrimidine type.

6. Photographic light-sensitive silver haldie material according toclaim 1, wherein said material also includes a development acceleratorof the polyoxyalkylene type.

7. Photographic light-sensitive silver halide material according toclaim 1, wherein said emulsion is a gelatino silver halide emulsion.

References Cited UNITED STATES PATENTS 2,728,663 12/1955 Allen et al.96109 2,728,665 12/1955 Leubner et al. 96l09 2,728,666 12/1955 Carrollet al. 96l09 2,728,667 12/1955 Knott et a1. 96l09 2,732,302 1/1956 Knottet al. 96l09 3,432,304 3/1969 Saleck et al 96l09 FOREIGN PATENTS 537,0232/1957 Canada 96l09 WILLEAM D. MARTIN, Primary Examiner 5 R. M. sPEERAssistarfi EXamin er

